The present invention relates to aggregate for feeding fuel from a supply tank to an internal combustion engine of a motor vehicle.
More particularly, it relates to such an aggregate which has a feed pump with a disk-shaped impeller rotating in a pump chamber, arranged so that between the end surfaces of the impeller and the associated end surfaces of the pump chamber, substantially parallel axial gaps are provided.
Aggregates of the above-mentioned general type are known in the art. In a known feed aggregate in which the above-mentioned axial gaps are maintained between the mutually parallel end surfaces of the impeller and the mutually parallel end walls of the pump chamber, one axial gap can move to zero while another axial gap can correspondingly increase. Since the impeller is displaced due to corresponding action in the direction of the rotary axis in the pump chamber, the impeller is blocked in its disadvantageous eccentric position, because no hydraulic force acts on the impeller and moves it back to its central position.